CHRONOS‐3: Randomized phase III study of copanlisib plus rituximab/placebo in relapsed indolent Non-Hodgkin Lymphoma (INHL)

Introduction: Rituximab (R)-based therapies are standard for patients (pts) with relapsed advanced iNHL. Copanlisib (C) is a PI3K inhibitor approved as monotherapy for relapsed follicular lymphoma (FL) in pts who have had ≥2 prior systemic therapies. We report primary data from the Phase III CHRONOS-3 study of treatment with C+R vs placebo (P)+R in relapsed iNHL (NCT02367040). Methods: Pts with relapsed iNHL who were progression-free and treatment-free for ≥12 months (mo) after last R-based therapy or unwilling/unfit to receive chemotherapy were randomized 2:1 to receive C+R or P+R. C 60 mg/P was given i.v. on days 1, 8, and 15 (28-day cycle); R 375 mg/m2 was given i.v. on days 1, 8, 15, and 22 during cycle 1 and on day 1 of cycles 3, 5, 7, and 9. Primary endpoint: centrally assessed progression-free survival (PFS). Secondary endpoints: objective response rate (ORR), duration of response, complete response rate (CRR), overall survival (OS), and treatment-emergent adverse events (TEAEs). The data cut-off date was August 31, 2020. Results: 307 pts were randomized to C+R and 151 to P+R. FL was the most common lymphoma histology subtype (60.0%), followed by marginal zone (MZL, 20.7%), small lymphocytic (SLL, 10.9%), and lymphoplasmacytic/Waldenström macroglobulinemia (LPL/WM, 8.3%). Median age was 63 years (range 28-91). With a median follow-up of 19.2 mo, the primary study endpoint was met: C+R significantly reduced the risk of disease progression/death vs P+R (hazard ratio [HR] 0.52 [95% CI 0.39, 0.69]; 1-sided p = 0.000002); median PFS was 21.5 mo (95% CI 17.8, 33.0) vs 13.8 mo (95% CI 10.2, 17.5), respectively. Reductions in risk of progression/death were seen across all histology subtypes (HR [95% CI]): FL 0.580 [0.404, 0.833]; MZL 0.475 [0.245, 0.923]; SLL 0.243 [0.111, 0.530]; LPL/WM 0.443 [0.160, 1.231]. ORRs were 80.8% (CRR 33.9%) for C+R and 47.7% (CRR 14.6%) for P+R. Higher ORRs and CRRs were seen across all iNHL subtypes with C+R treatment. Median OS was not